Comeback: Paul Casey's second 66 gives him 3-shot lead after 36 holes at Memorial Tournament

Bubba Watson tees off on the 18th hole during the second round of the Memorial golf tournament Friday, May 30, 2014, in Dublin, Ohio. (AP Photo/Jay LaPrete)
(The Associated Press)

Chris Stroud, left, shakes hands with Hideki Matsuyama, of Japan, following the second round of the Memorial golf tournament on Friday, May 30, 2014, in Dublin, Ohio. (AP Photo/Darron Cummings)
(The Associated Press)

Chris Kirk tees off on the 14th hole during the second round of the Memorial golf tournament Friday, May 30, 2014, in Dublin, Ohio. (AP Photo/Jay LaPrete)
(The Associated Press)

There were dark times over the past few years when Paul Casey wondered if maybe he was done with golf.

A painful divorce and a series of painful injuries made Casey, once the No. 3-ranked player in the world, doubt himself and his abilities.

Not now, though. Casey sits atop the lead at the Memorial Tournament, a wiser man with a different perspective.

Casey shot his second 6-under 66 in a row Friday to forge a three-stroke lead over Bubba Watson through 36 holes at Muirfield Village in the tournament founded and hosted by Jack Nicklaus.

Rory McIlroy, who was up by three shots after a glittering 63 in the opening round, had three double-bogeys in a row in a 78 that dropped him all the way into a tie for 24th.

On this day, however, the major headlines revolved around Casey, once a budding star in the game, a three-time European Ryder Cupper, who had all but fallen off the golf map not so long ago.

At his low point, a lost Casey didn't know if he would ever be competitive again.

"Standing in the middle of the fairway and you can't hit the green, or you're standing on the tee and you can't hit the fairway," he said. "Lots of times. And I did it out here, that was the thing. It's not like I kind of just disappeared and just went off the grid for a while. I was battling through. And that was quite tough, trying to play tournament-level golf and I wasn't able to."

A healthier, happier Casey won the Irish Open a year ago, his first victory on the European Tour in two years. Now he's in a relationship with a British TV personality, Polyanna Woodward, and will become a father for the first time when their son is born in September.

Smiling broadly while answering questions about his resurgence, Casey said he had learned a lot from the how far he had come.

"I have a very good perspective on things — I can't think of a better word," he said. "I know where everything fits now in my life. I don't necessarily have it figured out, but I know how things stack up in importance."

The 36-year-old Brit, who attended Arizona State, opened with a bogey in the opening round but rebounded with seven birdies for his 66. On Friday, he eagled the par-5 15th and added six more birdies against a couple of bogeys to stand at 12-under 132. Had he parred rather than bogeyed his final hole, he would have tied the tournament record for best 36-hole score.

Casey arose on Friday morning wondering what he would have to shoot to keep up with McIlroy, who had two eagles while battling a gimpy left knee to set a first-round scoring record at Muirfield Village.

But then McIlroy blew up with double-bogeys on three holes in a row in a 78 that left him at 3-under 141.

"I saw the numbers before I went out to play," Casey said. "But I have no idea how that happened."

McIlroy had a good idea how it happened, however.

"I missed fairways. That was the big thing," he said. "I didn't realize how thick the rough was until I got into it today."

Even on his round through the first three holes, his second shot caught tree branches on the 13th hole and kicked deeper into a thicket as he made a double on the par-4 hole. At the 14th, his approach came up short and landed in the creek in front of and to the right of the hole. Then at the 15th, his second shot ended up in the thick rough left of the par-5 hole and he double-hit the wedge shot for a one-shot penalty on his way to a 7.

"But it's not disastrous," McIlroy said. "Even though I had such a bad day, I'm still in it. So, going into the weekend, not exactly where I want to be — but it could be worse."

Watson, who won his second Masters last month, got to within a shot of Casey before bogeying the final two holes in a 69 that kept him three shots back. That was where he was at the start of the day, only now he's chasing Casey instead of McIlroy.

Chris Kirk shot a 70 and was alone in third at 136, with Hideki Matsuyama, who gained knowledge of the course from playing in a losing cause at last fall's Presidents Cup, shot a 67 and was at 137 along with Martin Flores (68). Hunter Mahan (70), Ryan Moore (70), Scott Langley (66) and Thorbjorn Olesen (67) were another shot back at 6-under.

"I can't look at the bogeys; I've got to look at where I'm at," Watson said. "If you told me it's my best two days around this golf course, I'd take it."

Casey said his down years hadn't given him amnesia when it came to knowing how to win.